Coralkin honest saltwater & reef care

🩺 Emergency Vet-Prep

Emerald Crab Emergency Vet-Prep

Marine vets are rare and it's easy to freeze in a crisis. This is the one page to have ready — how to find a vet, what to bring, what to tell them, and the questions to ask. Print it, keep it with your care notes.

Black & white saves ink and prints cleanly on any printer.

Not sure it's serious yet? Run the symptom checker or the water-test checker first — many worries turn out to be a husbandry fix.

Coralkin honest saltwater & reef care · coralkin.com
Emerald Crab — Vet-Prep

🔍 Find an aquatic vet

  • Search the WAVMA (World Aquatic Veterinary Medical Association) directory — or search "aquatic / exotics vet near me".
  • Call ahead: "Do you treat marine fish?" Few vets do — find and save one now, while things are calm.
  • Ask the exam fee when you call — knowing the cost up front removes the money-panic in a crisis.

📇 Fill this in now

My vet
My emerald crab
What I'm seeing

🚨 Is this an emergency now?

Quarantine and get help promptly if you notice any of these:

  • Picking at corals, zoanthids or small snails — it's hungry or too big; remove it (this is the main reason emeralds get pulled).
  • Ignoring bubble algae entirely — usually overfed on other food, or too small a crab for the job.
  • Failed moult / missing limbs — a chemistry or nutrition problem; stabilise parameters.

🚗 On the way / while you wait

✅ Do

  • Test your water NOW — salinity, ammonia, nitrite, nitrate, alkalinity and temperature — and correct anything obviously off.
  • Move the fish to a hospital / quarantine tank if you have one.
  • Keep it in its own stable tank water.
  • Keep the tank calm and dim.

⛔ Don't

  • Don't dose the display tank with OTC or shop “cures” blindly — copper and many meds are harmful to inverts and corals, and they mask the real cause.
  • Don't make a big, sudden parameter swing.
  • Don't add anything you can't explain the reason for.

🎒 What to bring

  • A recent, full water test — salinity, alkalinity, nitrate, temperature (and ammonia/nitrite/pH if you have them).
  • Photos plus a short video of what you’re seeing — it may not show it in the clinic.
  • A note of your system and how you feed.
  • Only if advised: the animal itself, in its own tank water.

🗣️ What to tell the vet / expert

Adult size
≈2 in across the carapace.
Minimum tank
10+ gallons with plenty of rockwork; usually kept one per tank.
Temperature
75–82°F (24–28°C).
pH
8.1–8.4.
Specific gravity
1.023–1.026 (reef-standard ≈35 ppt).
Other targets
Standard reef calcium and alkalinity support healthy moulting; like all inverts it has zero tolerance for copper.
Diet
Omnivore — eats bubble algae (Valonia) and other nuisance algae, plus meaty scraps and detritus. It will take pellets and mysis readily — which is exactly why an overfed crab ignores the algae.
Temperament
Nocturnal and can be territorial — usually one per tank. Reef-safe with caution (see below).
Reef-safe
With caution — a hungry or large emerald may pick at LPS, zoanthids, small snails or sleeping fish at night.
Natural range
Caribbean / Western Atlantic.

⚕️ Most marine illness starts with water quality or acclimation, not infection — bring a full set of parameters (salinity, alkalinity, nitrate, temperature). Marine-fish medicine is specialised and few vets treat fish, so call ahead. Copper and many OTC 'cures' are toxic to invertebrates and corals — never dose them in a reef display; treat a sick fish in a separate quarantine/hospital tank, and tell the vet exactly what you've already added.

❓ Questions to ask

  • Do you treat marine fish?
  • What are the likely causes — and could my water or acclimation be the cause?
  • What is the treatment plan, the likely cost, and what should I watch for?
  • How do I prevent this happening again?